A 43-YEAR-OLD former student was captured at a shopping centre after killing at least seven people at a small university in California.

One L Goh surrendered about an hour after the shooting at Oikos University, which serves the Korean community in Oakland.

Goh opened fire and shot several people, setting off an intense, chaotic manhunt that ended with his capture an hour later.

The suspect was detained at a Safeway supermarket about three miles from the university. A security guard approached because he was acting suspiciously. Goh told the guard that he needed to talk to police because he had shot people.

"He didn't look like he had a sign of relief on him. He didn't look like he had much of any emotion on his face," said shopper Lisa Resler.

Goh also called his father soon after the shooting and told him what happened, the police chief said. The father also called authorities, Mr Jordan said.

Police chief Howard Jordan initially reported that authorities recovered the weapon used during the rampage. But he later clarified that police only recovered enough ballistics evidence to determine that a handgun was used.

He added: "It's going to take us a few days to put the pieces together. We do not have a motive."

People connected to the school, including the founder and several students, described the gunman as a former nursing student at the university. Jordan said Goh is a South Korean national.

Police first received an emergency call at 10.33am local time on Monday reporting a woman on the ground bleeding. As more calls came in from the school, the first arriving officer found a victim suffering from a life-threatening gunshot wound, he said.

It was an "extremely chaotic scene", Jordan said. More officers arrived and formed a perimeter around the school in the belief that the suspect was still inside, he said.

Potential victims remained inside the building trapped by a locked door which officers were unable to open. Others were unable to flee because they were injured.

There were about 35 people in or near the building when gunfire broke out. Of the seven fatalities, five died at the scene and another two at the hospital. The wounded victims were in a stable condition and at least one person was released from the hospital.

"This unprecedented tragedy was shocking and senseless," Jordan said.

Soon after the shooting, heavily armed officers swarmed the school in a large industrial park near the Oakland airport and, for at least an hour, believed the gunman could still be inside.

Art Richards said he was driving past the university on his way to pick up a friend when he spotted a woman hiding in the bushes and pulled over. When he approached her, she said "I'm shot" and showed him her arm.

"She had a piece of her arm hanging out," Mr Richards said, noting that she was wounded near the elbow.

As police arrived, Mr Richards said he heard 10 gunshots coming from inside the building. The female victim told him that she saw the gunman shoot one person point-blank in the chest and one in the head.

Tashi Wangchuk, whose wife attended the school and witnessed the shooting, said he was told by police that the gunman first shot a woman at the front desk, then continued shooting randomly in classrooms.

Television footage showed bloodied victims on stretchers being loaded into ambulances. Several bodies covered in sheets were laid out on a patch of grass at the school. One body could be seen being loaded into a van.

Deborah Lee, who was in an English language class, said she heard five to six gunshots at first. "The teacher said 'Run' and we ran," she said. "I was OK, because I know God protects me. I'm not afraid of him."

The suspect's brother was killed in a car accident last year in Virginia while on active duty in the US army, according to the Stars and Stripes newspaper. The suspect attended the funeral of Sgt Su Wan Ko in Centreville, Virginia, after the March 8 2011 accident.